I am developing a C++ network application on Windows. I need to check if internet connection is there or not. I am using gethostbyname(), but it is giving incorrect information when the system is connected through a proxy. InternetCheckConnection() and InternetGetConnectedState() are also not giving reliable results under different conditions. Is there a reliable way to check for internet connectivity covering all the conditions such as proxy and VPN?
Update:
In our company network WinHttpGetProxyForUrl() is failing with the error ERROR_WINHTTP_AUTODETECTION_FAILED and WinHttpSendrequest() is failing with error ERROR_WINHTTP_NAME_NOT_RESOLVED.
In open network WinHttpSendrequest() is successful.